Warp knit cord



.. 2 1969 J. SKREPEK ETAL 3,422,641

WARP KNIT CORD Filed June 21, 1967 a I 2 INVENTORS /1 fkx e aefl Jvan JZK J. SKREPEK ETAL Jan. 21, 1969 WARP KN IT CORD Sheet Filed June 21, 1967 BAc/(BAR FRO/VTBAR United States Patent O 3,422,641 WARP KNIT CORD Jan Skiepek, Olany u vyskova, and Ivan Jakubec, Brno,

Czechoslovakia, assignors to Vyzkumny ustav pletarsky,

Brno, Czechoslovakia Filed June 21, 1967, Ser. No. 647,696

U.S. Cl. 66-169 3 Claims Int. Cl. D04b 21; 1304b 9/46 ABSTRACT OF THE DISCLOSURE A cord-like product is produced by warp knitting a narrow fabric having edge portions constiuted by one or two wales having loops in each course, each loop consisting of a single thread only and being connected to the central portion of the fabric by a diagonal underlap in a direction and under a tension to curl the edge portion. The central fabric portion consists of one to eight wales whose loops consist of two threads and have underlaps which extend in opposite coursewise directions to balance the tension on the central wales.

BACKGROUND OF THE INVENTION This invention relates to cords, and particularly to wrap knit cords and to a method of making the same.

Cords and very narrow ribbons were produced heretofore on braiding and plating machines. These machines reached their present stage of development some time ago, and appear incapable of substantial further development. They are fairly complex and correspondingly costly in their construction and maintenance, their operation requires the frequent attention of an operator because of the need for yarn bobbin changes, and they require more floor space per unit rate of output than other types of textile machinery. A representative cord braiding machine has six heads which jointly produce 90 to 120 meters of cord, such as shoe laces, per hour. The product is of high quality when competently made from good materials, but expensive.

An object of this invention is the production of cords at lower cost due to higher production rates than are available on braiding or plaiting machines without loss in quality. 7

SUMMARY OF THE INVENTION We have found that textile products having the properties of conventional round cords can be prepared at high rates on warp knitting machines of conventional types employed heretofore for making narrow fabrics such as surgical dressings, glove linings, decorative ribbons and the like.

The cords of the invention are narrow warp-knit fabrics whose longitudinal free edge portions are each constituted by at least one wale formed by single-thread loops in each course and whose central portion is formed by wales of loops of plural threads which are interposed coursewise between the edge portions. A diagonal underlap extends from each single-thread loop toward the central portion in a direction and under suflicient tension to cur-1 the edge portions toward each other.

The exact nature of this invention as well as other objects and advantages thereof will become apparent to those skilled in the art from consideration of the following specification relating to the annexed drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows the overall appearance of a cord of the invention in a perspective view, one end of the cord being sectioned;

3,422,641 Patented Jan. 21, 1969 DESCRIPTION OF PREFERRED EMBODIMENTS Referring now to the drawing in detail, and initially to FIG. 1, there is seen a cord of the invention as it appears to the unaided eye, the details of the yarn structure being not clearly discernible.

The cord 1 appears to be round, having a narrow longitudinal groove 2. In transverse section it appears to be U-shaped or of open annular shape, with the bulk of the material concentrated in the bight portion 3 of the U-shape.

When flattened out and inspected at some magnification, the fabric, as is seen in FIG. 2, is seen to consist of four warp-knit wales 4, 5, 6, 7. The two free edge portions of the fabric are formed by the wales, 4, 7 constituted by single-thread loops, and the wales 5, 6 of the central fabric portion are constituted by loops of which each is formed by two threads.

When released from flattening pressure, the two edge portions of the fabric curl upward into the U-shape of the cord 1 illustrated in FIG. 1. Curling is caused by the tension in the underlaps 8 which pull each single-thread loop of the marginal wales 4, 7 toward the doublethread loops of the central wales 5, 6. The underlaps of the latter extend symmetrically toward both sides so that the central portion of the fabric does not tend to curl.

The fabric of FIG. 2 was knit from six threads on a Raschel knitting machine manufactured in Czechoslovakia under the trade name Araknit. The machine has two guide bars and is provided with 1250* compound knitting needles arranged on a single needle bar having a working width of 2500 mm. When the machine is operated at its normal speed of 800 r.p.m., and threaded for simultaneously knitting 300 cords of the illustrated type, an hourly output rate of 10,000 to 15,000 meters of cord is readily maintained. One warp beam or one set of two warp beams can hold enough yarn to supply the machine for two hours. The floor space occupied by conventional machines capable of similar production.

As is shown in FIG. 3, portions of the yarn guides were threaded on the front bar and the back bar in a pattern of three and four yarns,

to produce the fabric of FIG. 2 and another fabric having three central wales 5', 5", 6' of loops, each loop being constittued by two threads, and the central wales interposed between two marginal wales 4, 7 identical with the wales of the fabric shown in FIG. 2. The guide bars were operated by pattern chains in the following manner:

Back guide bar, 1-2/l-01 Front guide bar, l-O/ 1-2) and repeat 3 wale 13 constituted by loops consisting of two threads each.

As is seen in FIG. 5, the guide bars of the afore-described Raschel knitting machine were threaded in part as follows:

Back guide bar, Front guide bar,

to produce the fabric of FIG. 4 and another fabric of the invention in which three wales 14, 15, 16 were interposed coursewise between two edge portions substantially identical with those of the fabric seen in FIG. 4.

The lapping movements of the guide bars were controlled by pattern chains in the following manner:

Back guide bar, 2-3/1-0 Front guide bar, 10/ 2-3 The two cords produced by the threading pattern of FIG. differed from each other in cross section, but were otherwise similar to the cord shown in FIG. 1.

The yarns associated with the two guide bars are identified in FIGS. 2 and 4 by shading or the omission of shading, and it is seen that yarns of the two guide bars alternatingly form the single thread loops of the marginal wales in successive courses.

The several cords produced on a single warp knitting machine according to the invention may be wound on a batching roller in a conventional manner. It is preferred, however, to lead each cord to a separate station of a winding machine on which individual bobbins of cord are wound, and to transfer the bobbins to further processing equipment which may be entirely conventional. As has been shown in FIGS. 3 and 5 by way of example, cords differing from each other in the number of threads may be produced simultaneously on the same knitting machine, and may be used for different purposes.

The cords of the invention may be knit from all conventional yarn types. We have successfully used yarns of natural and synthetic fibers, yarns made from staple fibers and continuous filaments, textured fibers, and fiber blends without difficulties.

The loops of central wales are formed by two threads and are under balanced coursewise tension by underlaps extending in opposite direction. They therefore do not contribute to the curling action which takes place imand repeat 4 mediately as the fabric leaves the knitting needles, and

we have not succeeded in producing cord-like fabrics of the U-shaped cross section illustrated in FIG. 1 with more than eight wales of double-thread loops. We have also encountered diificulties when more than two wales of single-thread loops constitute each free edge portion, and no compensatory advantages are achieved by a greater number of single-thread wales.

The term thread, as employed herein, is not necessarily limited to a thread consisting of a single strand of filamentous material, but each thread may consist of several associated yarns jointly extending through the fabric.

Other modifications and variations of the present invention are possible in the light of the above teachings. It is to be understood, therefore, that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described.

We claim: 1. A warp knit cord comprising: (a) two longitudinal, free edge portions, each edge portion being constituted by at least one wale having a loop formed by a single thread in each course; and

(b) a central portion including at least one wale having a loop formed by a plurality of threads in each course and being interposed coursewise between said free edge portions,

(1) a diagonal underlap extending from each of said loops of said edge portion toward said central portion in a direction and under a tension to curl said edge portions towards each other.

2. A cord as set forth in claim 1, wherein the number of wales in said central portion is between one and eight.

3. A cord as set forth in claim 1, wherein the number of said wales in each of said edge portions is the same.

References Cited UNITED STATES PATENTS 500,165 6/1893 Spooner 66-195 1,890,055 12/1932 Grumbach 66-172 2,078,050 4/1937 Beniston 66-195 WM. CARTER REYNOLDS, Primary Examiner.

US. Cl. X.R. 

